1. Field of the Invention
The present invention relates to a stator for a dynamo-electric machine constructed by laminating steel plate, the stator including a stator core formed with slots which extend in the axial direction and are spaced in the circumferential direction, and relates to a method for the manufacture thereof.
2. Description of the Related Art
FIG. 25 is a partial cross section of a conventional stator for a dynamo-electric machine. A stator core 1 constructed by laminating silicon steel plate is formed with slots 2 which extend in an axial direction and are spaced in a circumferential direction. A winding is formed by winding a conductor 3 composed of a copper wire conductor main body coated with enamel into the slots 2, which have an epoxy resin insulation coating 4 on an inner wall surface. Wedge 5 are disposed in entrance portions of the slots 2 to prevent the winding from protruding radially inwards from the slots 2.
In a stator for a dynamo-electric machine of the above construction, the cross-sectional shape of the conductor 3 is circular and spaces exist between adjacent conductors 3, lowering the space factor (the ratio of the space occupied by the conductors 3 in the slot 2). The diameter of the conductor 3 can be made thinner in order to increase the space factor of the conductor 3, but the number of winds of the conductor 3 increases proportionately, reducing productivity and the mechanical strength of the conductor 3 is also lowered, increasing the likelihood of breakages. Thus, one problem has been that the limit to improvement of the space factor of the conductor 3 has been about 40 to 50 percent and it has not been possible to raise the space factor beyond that.
The present invention aims to solve the above problems and an object of the present invention is to provide a stator for a dynamo-electric machine having improved manufacturing performance and enabling the space factor of the conductor to be raised, and to provide a method for the manufacture thereof.
To this end, according to the present invention, there is provided a stator for a dynamo-electric machine comprising a winding including a conductor having a rectangular cross-sectional shape in a direction perpendicular to an axial direction, an overall shape of the conductor being a crank shape when flattened out, the conductor comprising: straight portions laminated within slots; and bridge portions connecting the straight portions to each other, the bridge portions protruding from both end surfaces of the stator core in the axial direction.
According to another aspect of the present invention, there is provided a method for manufacturing a stator for a dynamo-electric machine, the method comprising: a step of joining the teeth into an annular shape by engaging the wedges in the entrance portions of the slots; a step of installing in the teeth a block-shaped winding formed by lamination by winding the conductor for a number of laps; and a step of engaging the engaging portions of the teeth in the engaged portions of the core back.
According to still another aspect of the present invention, there is provided a method for manufacturing a stator for a dynamo-electric machine, the method comprising: a step of installing in the teeth a block-shaped winding formed by lamination by winding the conductor for a number of laps, the teeth being joined in advance into an annular shape by means of a thin connecting portion at a radially inner portion; a step of engaging the engaging portions of the teeth in the engaged portions of the core back; and a step of cutting the connecting portions.